Cylinder structure for rotary vane type vacuum pump

ABSTRACT

The present invention relates to a cylinder structure for a rotary vane type vacuum pump which is capable of preventing a high pressure gas in a discharging port from flowing beyond vanes in the direction of a suction portion for thereby implementing a high vacuum state, decreasing a time required for obtaining a high vacuum state, and decreasing a noise. In a cylinder structure of a rotary vane type vacuum pump, a vane formed of a single plate shaped member and having a certain length is inserted into a vane engaging hole formed in the rotor, an inner diameter of the cylinder is processed to have the same diameter as the diameter of the pumping hole which passes through the center of the rotor, and both ends of the vane closely contacts with the pump hole when the vane is rotated in the pumping hole based on the rotation of the rotor in a rotary vane type vacuum pump which includes a suction port for sucking a gas from a vacuum facility into a pumping hole, a cylinder having a discharging port for discharging the gas from the pumping hole to the outside, and a rotor which is rotated in the pumping hole of the cylinder and is installed therein an eccentric method and includes a rotating vane which is closely contacted with the inner wall of the cylinder,

BACKGROUND OF THE INVENTION

[0001] 1 . Field of the Invention

[0002] The present invention relates to a cylinder structure of a rotary vane type vacuum pump, and in particular to an improved cylinder structure for a rotary vane type vacuum pump which is capable of maximizing a pumping efficiency of a vacuum pump and significantly decreasing a noise using one integral vane.

[0003] 2. Description of the Background Art

[0004] In a rotary vane type vacuum pump, a rotor is eccentrically installed in the interior of a cylinder. A vane is installed in such a manner that the vane passes through the center of the rotor. The vane is closely contacted with an inner surface of the cylinder and is rotated for thereby sucking and compressing a gas from a certain facility which needs a vacuum state and discharging the compressed gas to the outside.

[0005]FIGS. 1 through 3 are views illustrating a conventional cylinder structure of a rotary type vane type vacuum pump.

[0006] As shown therein, a circular pumping hole 2 is formed in the interior of a cylinder 1. A circular rotor 5 which is rotated by an external driving force is provided in the interior of the pumping hole 2. A portion of the rotor 5 has a continuous contact state with a wall of the pumping hole 2(an inner surface of the cylinder) between a suction port 3 and a discharging port 4. A first vane 7 and a second vane 8 having the same length are engaged in a vane engaging hole 6 which passes through the center of the rotor 5. A space 6 a in which a certain oil pressure is formed is formed between both vanes 7 and 8 in a state that the first vane 7 and the second vane 8 contact with the inner surface 1 a of the cylinder 1. The suction port 3 and the discharging port 4 are formed at both sides of the contact point of the inner surface of the rotor 5 and the cylinder 1, so that the rotor 5 sucks and compresses a gas from a vacuum facility through a pump suction port 3 and discharges the compressed gas to the outside.

[0007] As shown in FIGS. 1 through 3, the pumping hole 2 is formed in a circular shape. The rotor installed in the pumping hole 2 is eccentric in one direction, so that the distance T between both ends of the vanes 7 and 8 are varied in accordance with a rotation angle of the rotor 5.

[0008] Namely, as shown in FIG. 1, when the vanes 7 and 8 are positioned in a horizontal state at an angle of 0°, the distance T₁ between both ends of the vanes 7 and 8 is minimum, and when the vanes 7 and 8 are positioned in a vertical state at an angle of 90°, the distance T₂ between both ends of the vanes 7 and 8 is maximum.

[0009] Since the distance T between both ends of the vanes 7 and 8 is varied in accordance with a rotation angle of the rotor 5, a certain space 6 a is formed between the vanes 7 and 8, so that the vanes 7 and 8 positioned at the maximum distance T₂ are moved outwardly by a centrifugal force and a pressure applied to the space 6 a, and at the minimum distance T₁, the vanes 7 and 8 are moved into the space 6 a, so that the vanes 7 and 8 are continuously contacted with an outer surface of the pumping hole 2(the inner surface 1 a of the cylinder 1).

[0010] The pumping operation of the conventional cylinder will be explained with reference to the accompanying drawings.

[0011] When the rotor 5 is rotated by an external force, the rotor 5 is rotated, and the vanes 7 and 8 engaged thereto are rotated in such a manner that the vanes 7 and 8 are closely contacted with an outer surface 1 a of the pumping hole 2.

[0012] When the vanes 7 and 8 are positioned at an angle of 90° as shown in FIG. 2, from this time, the vanes 7 and 8 are rotated in a clockwise direction, so that the fluid in the left side of the pumping hole 2 is compressed for thereby moving the fluid to the side of the vanes 7 and 8, and the gas is flown into the right side pumping hole 2 through the vacuum facility connected through the suction port 3.

[0013] As the vanes 7 and 8 are continuously rotated, when the vanes 7 and 8 are positioned at the portion shown in FIG. 3, the amount of the fluid compressed by the vane 8 is maximized, and then the valve 9 is opened, so that the fluid is discharged through the discharging port 4. As the vanes 7 and 8 are continuously rotated in the pumping hole 2, the fluid is repeatedly pumped through the discharging port 4.

[0014] However, in the conventional cylinder structure, the pressure of the gas before the fluid is compressed by the vanes and discharged through the discharging port 4 is too high. In addition, since the oil supplied to lubricate the inner surface 1 a of the cylinder is gathered in a narrow space, the vanes which pushes the fluid by the pressure of the fluid are moved in the direction of the space 6 a formed in the center portion of the rotor 5, so that the fluid compressed is flown beyond the vanes in the direction of the suction side for thereby decreasing the pumping efficiency. When the gas is compressed, since the compressed gas is flown beyond the vanes based on the phenomenon that the vanes are backwardly moved, it takes long time so that the pump has a high vacuum state, and it is impossible to implement a maximum vacuum state. In addition, a big noise occurs due to the vibrations of the vanes 7 and 8.

[0015] In addition, since there is a difference in the lengths of the vanes which are repeatedly moved in the engaging hole 6 in the forward and rearward directions based on the rotation angle of the rotor, the moving distances of the first and second vanes engaged to the rotor are increased, so that the friction ratio of the vanes is increased, and the lift span of the same is decreased.

SUMMARY OF THE INVENTION

[0016] Accordingly, it is an object of the present invention to provide a cylinder structure for a rotary vane type vacuum pump which overcomes the problems encountered in a conventional cylinder structure.

[0017] It is another object of the present invention to provide a cylinder structure for a rotary vane type vacuum pump which is capable of preventing a high pressure gas in a discharging port from flowing beyond vanes in the direction of a suction portion for thereby implementing a high vacuum state, decreasing a time required for obtaining a high vacuum state, and decreasing a noise.

[0018] To achieve the above object, there is provided a cylinder structure for a rotary vane type vacuum pump in which a vane formed of a single plate shaped member and having a certain length is inserted into a vane engaging hole formed in the rotor, an inner diameter of the cylinder is processed to have the same diameter as the diameter of the pumping hole which passes through the center of the rotor, and both ends of the vane closely contacts with the pump hole when the vane is rotated in the pumping hole based on the rotation of the rotor in a rotary vane type vacuum pump which includes a suction port for sucking a gas from a vacuum facility into a pumping hole, a cylinder having a discharging port for discharging the gas from the pumping hole to the outside, and a rotor which is rotated in the pumping hole of the cylinder and is installed therein an eccentric method and includes a rotating vane which is closely contacted with the inner wall of the cylinder.

[0019] In addition, in the present invention, a streamline shaped curved portion is formed at both ends of the vane for thereby implementing a closer contact with an inner surface of the cylinder.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will become better understood with reference to the accompanying drawings which are given only by way of illustration and thus are not limitative of the present invention, wherein;

[0021]FIG. 1 is a cross-sectional view illustrating a cylinder structure of a conventional vacuum pump;

[0022]FIGS. 2 and 3 are cross-sectional views illustrating an operation state of a conventional cylinder structure;

[0023]FIG. 4 is a cross-sectional view illustrating a cylinder structure according to the present invention; and

[0024]FIGS. 5 through 7 are cross-sectional views illustrating an operation of a cylinder structure for a rotary vane type vacuum pump according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The present invention will be explained with reference to FIGS. 4 through 7. In the description of the present invention, the same elements as the conventional cylinder structure are given the same reference numerals for a simplification of the description.

[0026] As shown in FIG. 4, a pumping hole 10 formed in the interior of a cylinder 1 is formed in such a manner that all diameters R passing through the center of a rotor 5 are same differently from the conventional art in which the cylinder 1 has a pumping hole 10 formed in a full circular shape. Namely, in the present invention, the pumping hole 10 is formed in a distorted circular shape.

[0027] A rotor 5 is eccentrically formed in the interior of the pumping hole 10 in such a manner that the rotor 5 is contacted with an inner side between a suction port 3 and a discharging port 4, and one plate-shaped vane 11 is inserted into the engaging hole 6 of the rotor 5.

[0028] The vane 11 passes through the center portion of the rotor 5. When processing the pumping hole 10, all diameters R passing through the center of the rotor 5 are same, and the diameter R is the same as the length of the vane 11.

[0029] When an outer surface of the pumping hole 10 is formed, as shown in FIG. 4, even when the vane 11 is positioned at an angle of 0°(horizontal) or 90°(vertical), since the diameter of the pumping hole 10 is the same as the length of the vane 11, it is possible to enhance the contact ability between the vane 11 and the outer surface of the pumping hole 10.

[0030] Since the vane 11 is formed in an integral shape, even when the vane 11 is positioned at an angle of about 210° in which the pressure of the fluid is highest (as shown in FIG. 3), the vane 11 is not backwardly moved by the pressure of the fluid, so that it is possible to enhance the vacuum ability of the pump by an enhanced sealing performance.

[0031] In the present invention, a streamlined curved portion 12 is formed at both ends of the vane 11, so that it is possible to enhance a contact ability between the vane 11 and an outer surface of the pumping hole 10 when the vane 11 is rotated along the outer surface of the pumping hole 10, and the abrasion of the vane 11 is prevented.

[0032] The operation of the present invention will be explained with reference to the accompanying drawings.

[0033]FIG. 5 is a view illustrating that the vane 11 is positioned at 0°(horizontal). The operation of the present invention will be explained assuming that the rotor 5 is operated when the wane 11 is positioned at an angle of 0°.

[0034] When the rotor 5 is rotated in a clockwise direction(right direction in the drawings), the vane 11 is rotated in the clockwise direction. At an initial operation stage, since a pressure is not applied to the side of the discharging port 4, the fluid is not discharged. The volume of the space A(suction space) of the pumping hole 10 is expanded in the side of the suction port 3 for thereby gradually forming a vacuum state, and a gas is flown from the vacuum facility through the suction port 3.

[0035] When the rotor 5 is continuously rotated, since the volume of the space B(discharging space) in the side of the discharging port 4 is decreased, the gas in the space B is compressed. A high pressure-compressed gas is discharged to the outside through the valve 9 through the discharging port 4. At this time, the volume of the space A is continuously increased, so that a space A has a negative pressure. Therefore, the gas is flown from the vacuum facility into the space A.

[0036] When the vane 6 is positioned as shown in FIG. 6, the discharging operation of the compressed gas is ended, and the gas in the left space B is compressed. When the upper portion of the vane 11 passes through the inlet portion 3 as shown in FIG. 5, the space C is disconnected with the space A and the space B for thereby forming a sealed space. As the rotor 5 is continuously rotated, the space A of FIG. 5 is expanded, and the gas is sucked from the vacuum facility, and the volume of the space B is decreased, and the gas is compressed and is discharged through the discharging port 4. The gas in the space C is compressed when the vane 11 is positioned as shown in FIG. 6. The above-described operations are repeatedly performed. Therefore, the gas from the vacuum facility is sucked, compressed and discharged to the outside. When the vane 11 is positioned as shown in FIG. 7, the pressure in the space B near the discharging port 4 becomes a maximum state. The high pressure acts to push the vane 11 in the direction of the left lower side. At this time, the right lower portion of the vane 11 is closely contacted with an inner surface 1 a of the cylinder 1, so that there is no space for the vane 11 to be backwardly moved. Therefore, the vane 11 is not backwardly moved along the engaging hole 6 like the conventional art.

[0037] In addition, since the curved portion 12 is formed at both ends of the vane 11, even when the vane 11 is positioned at a certain portion, it is possible to implement a stable sealed state between the vane 11 and the inner surface 1 a of the pumping hole 10, so that it is possible to enhance a vacuum ability and pumping force of the vacuum pump.

[0038] As described above, in the present invention, an integral vane is engaged to the rotor, and the rotor is eccentrically engaged in the pumping hole. All diameters passing through the rotation center of the rotor are same. Therefore, as the rotor is rotated, both ends of the vane are closely contacted with an inner surface of the cylinder, so that the vane is not moved by a high compression pressure for thereby maximizing the pumping efficiency of the vacuum pump and decreasing a time required for implementing a high vacuum state. In addition, since one integral vane is used, the construction of the system is simplified, and the noise is significantly decreased.

[0039] As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims. 

What is claimed is:
 1. In a rotary vane type vacuum pump which includes a suction port for sucking a gas from a vacuum facility into a pumping hole, a cylinder having a discharging port for discharging the gas from the pumping hole to the outside, and a rotor which is rotated in the pumping hole of the cylinder and is installed therein an eccentric method and includes a rotating vane which is closely contacted with the inner wall of the cylinder, a cylinder structure of a rotary vane type vacuum pump in which a vane formed of a single plate shaped member and having a certain length is inserted into a vane engaging hole formed in the rotor, an inner diameter of the cylinder is processed to have the same diameter as the diameter of the pumping hole which passes through the center of the rotor, and both ends of the vane closely contacts with the pump hole when the vane is rotated in the pumping hole based on the rotation of the rotor.
 2. The structure of claim 1, wherein a streamline shaped curved portion is formed at both ends of the vane for thereby implementing a closer contact with an inner surface of the cylinder. 